Improving cost estimates for advanced low-carbon power plants

•Cost estimates for advanced low-carbon technologies are widely sought but flawed.•Two categories of questions frame most cost analyses: “What if?” and “What will?”.•Conventional “bottom-up” costing is appropriate only for hypothetical (what if) designs.•A hybrid method of bottom-up and top-down costing is proposed for “what will” it cost.•This approach offers more realistic projections of future costs and the experience needed.